1. Technical Field
The present invention relates to a method and apparatus for additive manufacturing of three-dimensional articles.
2. Related Art
Freeform fabrication or additive manufacturing is a method for forming three-dimensional articles through successive fusion of chosen parts of powder layers applied to a worktable via an apparatus.
Such an apparatus may comprise a worktable on which the three-dimensional article is to be formed, a powder dispenser, arranged to lay down a thin layer of powder on the work table for the formation of a powder bed, a ray source for delivering energy to the powder whereby fusion of the powder takes place, elements for control of the ray given off by the ray source over the powder bed for the formation of a cross section of the three-dimensional article through fusion of parts of the powder bed, and a controlling computer, in which information is stored concerning consecutive cross sections of the three-dimensional article. A three-dimensional article is formed through consecutive fusions of consecutively formed cross sections of powder layers, successively laid down by the powder dispenser.
There is a demand for additive manufacturing techniques which is capable of building larger and larger three-dimensional articles.
An increase of the build volume may require multiple beam sources which may lead to process difficulties in order to keep the beam spot quality and beam spot positioning equal over the entire build area.